Studies of induction of infectious virus from virogenic SV40 transformed cells are being carried out. In particular, the mechanism of such induction, the relationship to breaks in the host DNA, the kinetics of the excision process, and the time course of DNA synthesis subsequent to induction are being analyzed. In addition, we are delineating the reasons for the differences in permissivity in SV40 virus replication in different virus transformed cell lines which differ in their degree of inducibility. Studies on the cell surface concern proteases which are secreted by normal and transformed cells. We are exploring the mechanism by which certain serine proteases result in changes of the phenotype of normal and transformed cells, the mechanism of the secretion, and whether such secretion results in loss of cell surface material from both normal and cancer cells. Studies on virus transformed antibody producing cells are concerned with the creation of a cell line capable of indefinite growth which will produce monospecific antibody. Human lymphoid cells are being sensitized to a relevant antigen, such as digoxin, and these cells are then being exposed to EBV virus in order to create autonomous, transformed cell lines which will produce human antibody. Antibody produced in this way will be of inestimable value in the diagnosis and therapy of various human diseases. BIBLIOGRAPHIC REFERENCES: Roblin, R., Albert, S.O., Gelb, N.A. and Black, P.H. Contact-inhibited revertant cell lines isolated from SV40-transformed cells. V. Sulfated acid mucopolysaccharide - metabolism in 3T3, SV3T3 and revertant cells. Biochemistry 14:347-357, 1975. Black, P.H., Chou, I.H. and Roblin, R.O. Differences in surface membrane components between normal, viral-transformed and revertant cells. In: Proc. of the XIth Internat. Cancer Congress, Vol. 1, Cell Biology and Tumor Immunology (P. Bucalossi, U. Veronesi and N. Cascinelli, eds.), Excerpta Medica, Amsterdam, 1975, pp. 119-129.